The present invention relates to a cleaning method (hereinafter, ordinary cleaning methods, surface treatment methods and the like will be generically referred to as a cleaning method) applicable to many electronic parts such as electronic materials, magnetic materials, optical materials, ceramics, etc. and the production process of the electronic parts. In particular, the present invention relates to a method of producing a semiconductor apparatus by use of a preferable cleaning method and to a semiconductor apparatus produced by the method.
The structure of a general semiconductor apparatus is such that, as described in patent document 1, a thermal oxide film is provided on a Si substrate, or an insulating film is formed on the Si substrate by use of CVD (Chemical vapor Deposition) or PVD (Physical vapor Deposition), a semiconductor film is further provided thereon, and these films are processed to form semiconductor devices. Therefore, at the time of forming the semiconductor devices by processing the films, the film in the subsequent step is formed in such a manner as to cover a peripheral end portion of the underlying substrate or an underlying film, so that when the covering is insufficient, the film of this portion constitutes a source of dust, which would hamper the production of the semiconductor apparatus.
A general cleaning method for a semiconductor substrate (silicon wafer) is a method in which the substrate (wafer) is cleaned by immersing it in a cleaning liquid such as diluted hydrofluoric acid, a mixed liquid of ammonia and aqueous hydrogen peroxide, etc. for a predetermined period of time. Incidentally, a mixed liquid of ammonia, aqueous hydrogen peroxide and ultra-pure water is described, for example, in “Handbook of Semiconductor Wafer Cleaning Technology”, written by Wern Kern, published by Noyes Publications (1995), p. 517.
In addition, as a method of removing the contamination source present at a peripheral end portion of a wafer, there is known a method in which the steps of photoresist application, patterning, dry etching and photoresist removal are repeated, as described in Japanese Patent Laid-open No. Hei 5-21724, and a method in which the peripheral end portion of the wafer is mechanically polished, as described in Japanese Patent Laid-open No. Hei 11-188590.